help.start();
help(solve);
example(panel.lines.tis);
demo(package = "base");
library("lmtest");
install.packages("lmtest");
install.packages("splm");
library(splm);
library();

x <- rnorm(50);
y <- rnorm(x);
plot(x,y);
ls()
rm(x,y)
n <- 10
n1 <- 1:n-1
n2 <- 1:(n-1)
rep(n1,times = 5)
rep(n1,each = 5)
5>13 & 5>2
is.nan(n1)
n1 <- c(n1,NA,0/0);
n1 = n1[1:5];
n2 = c("X", "Y")[rep(c(1,2,2,1), times = 4)]
labs <- paste(c("X"), 1:10, sep="");
summary(x)
fruit <- c(5, 10, 1, 20)
names(fruit) <- c("orange", "banana", "apple", "peach");
lunch <- fruit[c("apple","orange")]
mode(n2)
n <- as.character(n1)
n <- as.integer(n)
attributes(n)
x <- array(1:20, dim=c(4,5));
i <- array(c(1:3,3:1), dim = c(3,2));
x[i] <- 0
x[i]
Xb <- matrix(0, 5, 1)
ib <- cbind(1:5, "person")
Xb[ib] <- 1
 d <- outer(0:9, 0:9);
 fr <- table(outer(d, d, "-"))
 plot(as.numeric(names(fr)), fr, type="h",xlab="Determinant", ylab="Frequency")
fr0 <- outer(d,d, "-")

